JP2004245517A - Combustion controller for incinerator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a combustion controller for an incinerator capable of speedily corresponding to supply of condensed refuse having low ventilation property to avoid reduction of combustion amount. <P>SOLUTION: A primary combustion air supply means A for supplying primary combustion air, a primary combustion air heating means B for heating primary combustion air, and a control means for adjusting supply amount of primary combustion air by the primary combustion air supply means A and heating temperature of primary combustion air by the primary combustion air heating means B based on a combustion index showing a combustion condition of refuse in the incinerator are provided below a burning handling zone 5 for burning and handling refuse supplied into the incinerator by a refuse supply means 4. The control means compensates supply amount of primary combustion air to an increase side and compensates heating temperature of primary combustion air to a high temperature side when refuse supply efficiency showing refuse supply amount of the refuse supply means 4 rises. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention is based on a combustion index indicating the combustion state of the refuse supplied to the furnace by the dust supply means, the supply amount of the primary combustion air supplied below the incineration treatment zone for incinerating the refuse and the primary combustion air. The present invention relates to a combustion control device for an incinerator for adjusting a heating temperature.
[0002]
[Prior art]
In the combustion control device of the incinerator, as a first related art, when the oxygen concentration in the exhaust gas is at a normal value (during normal combustion at or below the upper limit concentration), heating of the primary combustion air is performed based on the calorific value of the dust. In addition to controlling the temperature, feedback control is performed to PID-control the supply amount of the primary combustion air based on the amount of steam generated in the boiler. When the oxygen concentration in the exhaust gas exceeds the upper limit concentration, the feedback control is performed. In some cases, the heating temperature of the primary combustion air is corrected to a higher temperature based on the rise amount, and the supply amount of the primary combustion air is limited at an upper limit (see Patent Document 1).
[0003]
Further, as a second conventional technique, the dust supply efficiency (the amount of dust supplied by the dust supply unit) is estimated from the operation speed of the dust supply unit that supplies dust into the furnace and the history of the dust supply amount, and the target waste incineration amount is determined. In order to achieve this, there is one that controls the operation speed of the dust supply means based on the dust supply efficiency (see Patent Document 2). As a third related art, the above-described dust supply efficiency, heat generation amount of dust, There is a device which controls the operation speed of the dust supply means based on the target heat generation amount (see Patent Document 3).
[0004]
[Patent Document 1]
JP-A-10-61932 (pages 2-5, FIGS. 1-6)
[Patent Document 2]
JP-A-7-269834 (pages 2-4, FIGS. 1-4)
[Patent Document 3]
JP-A-2002-349827 (pages 1-5, FIGS. 1-2)
[0005]
[Problems to be solved by the invention]
However, in the first prior art, when the oxygen concentration is a normal value, if the calorific value is not a low value, and low-permeability dust compressed and condensed in the dust pit is supplied, the response is delayed. there were. That is, when the oxygen concentration is the normal value, the change in the calorific value of the dust does not appear, so that the heating temperature of the primary combustion air is not controlled based on the calorific value of the dust, and the dust having low air permeability is supplied. This is because the control to increase the temperature of the primary combustion air is performed only after the surface area of the dust contacted by the combustion air decreases and the amount of combustion in the furnace decreases and the oxygen concentration increases.
Note that when the dust having low air permeability is supplied, the dust supply efficiency increases. However, the second and third prior arts disclose that when the dust efficiency increases, the dust efficiency increases. There is no specific description of the control of the primary combustion air.
[0006]
The present invention has been made in view of the above circumstances, and an object of the present invention is to be able to promptly respond to a case where condensed low-permeability refuse is supplied and avoid a decrease in the amount of combustion. An object of the present invention is to provide a combustion control device for an incinerator.
[0007]
[Means for Solving the Problems]
According to the first aspect of the present invention, there is provided a combustion control apparatus for an incinerator, wherein primary combustion air is supplied to a lower portion of an incineration zone for incinerating refuse supplied into the oven by dust supply means. A combustion air supply unit; and a control unit for adjusting a supply amount of the primary combustion air by the primary combustion air supply unit based on a combustion index indicating a combustion state of the refuse in the furnace. Means for correcting the supply amount of primary combustion air by the primary combustion air supply means to an increasing side when the dust supply efficiency indicating the amount of dust supplied by the dust supply means increases.
[0008]
According to the above configuration, when the control unit is performing control for adjusting the supply amount of the primary combustion air by the primary combustion air supply unit based on the combustion index indicating the combustion state of the refuse in the furnace, When the dust supply efficiency indicating the dust supply amount of the dust means increases, in the above-described air supply amount adjustment control, the primary combustion air supply amount by the primary combustion air supply means is corrected to increase.
That is, when the dust supply efficiency increases, the specific gravity of the dust increases, and the permeability is predicted to decrease.Therefore, the flow rate is increased by increasing the supply amount of the primary combustion air supplied below the incineration treatment zone, By increasing the air permeability to the dust, the surface area of the dust contacted by oxygen is increased to promote combustion, thereby preventing a decrease in combustion.
Accordingly, there is provided a combustion control device for an incinerator, which is capable of promptly responding to the supply of condensed dust having low air permeability and avoiding a decrease in the amount of combustion.
[0009]
A characteristic configuration of the invention according to claim 2 is that, in the invention according to claim 1, a drying treatment zone, a combustion treatment zone, and a post-combustion treatment zone are sequentially arranged in the incineration treatment zone from the upper side along the garbage transport direction. Wherein the control means corrects at least one of the air supply amount to the drying treatment zone, the air supply amount to the combustion treatment zone, and the total air supply amount to all the treatment zones to the increasing side. .
[0010]
That is, when the dust supply efficiency is increased, by increasing the air supply amount to the drying treatment zone, the drying speed of the dust in the drying treatment zone is increased, and it is possible to prevent a decrease in combustion due to a decrease in air permeability. .
In addition, when the dust supply efficiency is increased, the amount of air supplied to the combustion treatment zone is increased, so that the amount of refuse burned in the combustion treatment zone is increased. Can be prevented from occurring.
In addition, when the dust supply efficiency is increased, the air supply amount to all the treatment zones is increased, so that the drying speed of the garbage is increased in the drying treatment zone, and the garbage combustion amount is increased in the combustion treatment zone, and the radiant heat is increased. Combustion is promoted, and it is possible to prevent a decrease in combustion due to a decrease in air permeability.
Therefore, a preferred embodiment of a combustion control device for an incinerator that can avoid a decrease in the amount of combustion when condensed dust having low air permeability is supplied is provided.
[0011]
In the invention according to claim 3, the primary combustion air heating means for heating the primary combustion air supplied below the incineration zone for incinerating the refuse supplied into the furnace by the dust supply means, Control means for adjusting a heating temperature of the primary combustion air by the primary combustion air heating means based on a combustion index indicating a combustion state is provided. When the dust supply efficiency is increased, the heating temperature of the primary combustion air by the primary combustion air heating means is corrected to a higher temperature.
[0012]
That is, when the dust supply efficiency increases, the specific gravity of the dust increases, and a decrease in air permeability is predicted. Therefore, the heating temperature of the primary combustion air supplied below the incineration zone is increased. As a result, the air expands according to Boyle-Charles' law, the flow velocity increases, and the air permeability to the dust increases, thereby increasing the surface area of the dust contacted by oxygen to promote combustion, thereby preventing the occurrence of combustion reduction. it can.
Accordingly, there is provided a combustion control device for an incinerator, which is capable of promptly responding to the supply of condensed dust having low air permeability and avoiding a decrease in the amount of combustion.
[0013]
According to a fourth aspect of the present invention, in the invention according to the third aspect, the control means detects a furnace outlet temperature as the combustion index as adjustment control of the primary combustion air heating temperature based on the combustion index. Based on the detection information of the furnace outlet temperature detecting means, adjust the heating temperature of the primary combustion air to be high when the furnace outlet temperature is low, and to lower the heating temperature of the primary combustion air when the furnace outlet temperature is high. The point is to execute the control.
[0014]
As shown in the configuration of claim 3, when the dust supply efficiency increases, the heating temperature of the primary combustion air in the adjustment control is corrected to a higher temperature side. When the dust supply efficiency increases, the target value of the primary combustion air heating temperature based on the furnace outlet temperature is corrected to a higher temperature side, so that the combustion promotion control corresponding to the increase in the dust supply efficiency and the furnace outlet temperature are performed. The control of the heating temperature of the primary combustion air can be compatible.
Therefore, a preferred embodiment of a combustion control device for an incinerator that can avoid a decrease in the amount of combustion when condensed dust having low air permeability is supplied is provided.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a combustion control device for an incinerator according to the present invention will be described with reference to the drawings.
As shown in FIG. 1, a bucket 1 for picking up and transporting dust accumulated in a dust pit 20, a hopper 2 into which the dust picked up by the bucket 1 is put, and an incinerator 3 for removing dust in the hopper 2. A pusher mechanism 4 serving as dust supply means which reciprocates to push and supply the wastewater into the furnace; a stoker-type incineration zone 5 for incineration while transporting refuse supplied into the furnace by the pusher mechanism 4; An ash pit 6 for collecting incinerated ash from the zone 5, a steam turbine 8 supplied with steam from a waste heat boiler 7 for collecting heat generated in the furnace, and power generation driven by the steam turbine 8. A refuse incineration facility is provided so that the refuse incineration equipment is provided, and after the exhaust gas from the incinerator 3 is treated by an exhaust gas treatment unit 10 having a bag filter or the like, the exhaust gas is discharged from a chimney 11. .
[0016]
Although not shown in the drawings, the steam from the waste heat boiler 7 is stored in a steam reservoir in a state where the steam is heated by a steam heater arranged in a flue for sending exhaust gas from the incinerator 3 to be dried and vaporized, After the steam from the steam reservoir is supplied to the steam turbine 8 to drive the generator 9, the steam is condensed and finally returned to the waste heat boiler 7.
[0017]
The incineration treatment zone 5 includes a drying treatment zone 5a for drying the supplied dust and heating it to near the ignition point from the upper side (the side of the pusher mechanism 4) along the direction of transporting the dust in the furnace. A combustion treatment zone 5b for burning refuse and a post-combustion treatment zone 5c for ashing the burned trash are sequentially arranged. Each of the incineration zones 5a, 5b, and 5c is formed in a step-like manner so that the level of the incineration zone 5 becomes lower toward the lower side in the transport direction.
[0018]
Each of the treatment zones 5a, 5b, 5c has a fixed grate in a fixed state and a movable grate slidable with respect to the fixed grate, and the movable grate is fixed by operating a hydraulic cylinder (not shown). The dust is stirred while the dust on the incineration zone is sequentially transferred to the drying zone 5a, the combustion zone 5b, and the post-combustion zone 5c by sliding back and forth with respect to the grate. Then, the ash that has been incinerated in the post-combustion treatment zone 5c falls to the ash pushing mechanism 12 and is conveyed and accumulated in the ash pit 6 by the ash conveyor 13.
[0019]
Next, a primary combustion air supply means A for supplying primary combustion air below the incineration zone 5 and a primary combustion air heating means B for heating the primary combustion air supplied below the incineration zone 5 are provided. Is provided. This will be specifically described below.
[0020]
A main flow path 16 for allowing air sent from the blower 15 to flow to the air preheater 14, and a bypass flow path branching from the upstream side of the main flow path 16 to send air and join a downstream portion of the air preheater 14 And a main damper 18 for controlling the amount of air flowing through the main flow path 16 and a sub-damper 19 for controlling the amount of air flowing through the bypass flow path 17. A main temperature sensor Tm including a thermistor and a thermocouple for measuring the temperature of air flowing through the path 16 is provided. The air pre-heater 14 is provided with a steam supply system for heating the air by sending the steam stored in the steam reservoir.
[0021]
Depending on the opening degree of the main damper 18 and the opening degree of the sub damper 19, the mixing ratio between the air sent through the main passage 16 and heated by the air preheater 14 and the normal-temperature air sent through the bypass passage 17 And the temperature of the mixed air can be adjusted by the mixing ratio. Therefore, the primary combustion air heating means B is constituted by the main flow path 16, the bypass flow path 17, the main damper 18, the sub damper 19 and the like.
[0022]
A first flow path 21 is connected to a location downstream of a junction of the main flow path 16 and the bypass flow path 17, and is disposed downstream of the first flow path 21 below the processing zones 5 a, 5 b, and 5 c. A plurality of distribution paths 22 for guiding air to a plurality of wind boxes 23 are formed in a branched manner, and a flow sensor F1 that measures the flow rate of air to each distribution path 22 and a branch damper D1 that controls the flow rate of air are provided. ing. The air supplied to each of the distribution paths 22 passes upward from the wind box 23 through each of the processing zones 5a, 5b, and 5c, thereby promoting the combustion of dust. Accordingly, the first combustion air supply means A is constituted by the first flow path 21, the plurality of distribution paths 22, the plurality of wind boxes 23, the plurality of branch dampers D1, and the like.
[0023]
Although not particularly shown in the drawings, the main damper 18, the sub damper 19, and the plurality of branch dampers D1 are each set to an arbitrary opening degree by a hydraulic cylinder or an electric motor to control the air flow. Is configured. The flow rate sensor F1 is configured to output the flow rate of air per unit time as an electric signal by using an impeller type, a vortex type, or a pitot tube type.
[0024]
Secondary combustion air supply means for supplying secondary combustion air to the inside of the furnace above the incineration treatment zone 5 in order to perform secondary combustion of the combustion gas generated by the burning of the refuse in the incinerator 3 27 are provided. An oxygen concentration sensor 26 for detecting the oxygen concentration in the exhaust gas after the secondary combustion is provided in the flue of the exhaust gas from the incinerator 3.
[0025]
A gas temperature sensor 25 of a thermocouple type or the like for measuring the exhaust gas temperature at the furnace outlet position of the incinerator 3, that is, the furnace outlet temperature is provided. If the combustion state of the dust in the furnace is good, the temperature of the exhaust gas is an appropriate value, but if the combustion state of the dust in the furnace deteriorates and the amount of combustion decreases, the temperature of the exhaust gas decreases. The gas temperature sensor 25 constitutes a furnace outlet temperature detecting means for detecting the furnace outlet temperature as a combustion index indicating a burning state of dust in the furnace.
[0026]
As shown in FIG. 2, a control device 30 including a microprocessor, a semiconductor memory, and the like is provided. The control device 30 includes the main temperature sensor Tm, a plurality of flow sensors F1, a gas temperature sensor 25, and an oxygen concentration sensor. 26, and the respective detection information of a weight sensor 24 (see FIG. 1) for detecting the weight of the trash picked up by the bucket 1 and put into the furnace. On the other hand, the control device 30 outputs drive signals to the bucket 1, the pusher mechanism 4, the main damper 18, the sub damper 19, the plurality of branch dampers D1, and the like.
[0027]
Dust supply efficiency calculation means D for calculating the dust supply efficiency representing the amount of dust supplied by the pusher mechanism 4 is provided in the control device 30. The dust supply efficiency is estimated from the operation speed of the pusher mechanism 4 and the actual value of the dust input amount. Specifically, assuming a certain amount of garbage that stays from the hopper 2 to the combustion treatment zone 5 and is expected to enter the drying and combustion process in the future, the pusher for a predetermined time required to input the garbage amount is assumed. The dust input efficiency (tons / cycle) is obtained by dividing the input weight (tons / hour) of dust by the mechanism 4 by the moving average value of the operating speed (cycles / hour) of the pusher mechanism 4 at the same predetermined time. . Details are described in the above-mentioned Patent Documents 2 and 3.
[0028]
Further, the controller 30 includes an air amount adjustment control for adjusting the supply amount of the primary combustion air by the primary combustion air supply means A based on a combustion index indicating a combustion state of the dust in the furnace; A control means C for executing temperature adjustment control for adjusting the heating temperature of the primary combustion air by the primary combustion air heating means B based on the combustion index indicating the combustion state of the primary combustion air.
[0029]
In the air amount adjustment control, specifically, as shown by the solid line in the graph of FIG. 3, the control means C determines the primary order based on the waste heat value (kJ / kg) estimated from the material balance and the heat balance. The amount of combustion air is calculated, and further corrected by the amount of steam (the amount of steam generated from the waste heat boiler 7), the temperature at the furnace outlet, the burn-off point (the burn-off point of garbage on the combustion processing zone 5b), and the like. Set the target value of the supply amount of combustion air.
In addition, the temperature adjustment control is, as shown in a solid line graph in FIG. 4, the control means C controls the primary combustion air heating temperature based on the combustion index as the gas temperature sensor. 25, the heating temperature (target value) of the primary combustion air is increased when the furnace outlet temperature is low, and the heating temperature (target value) of the primary combustion air is increased when the furnace outlet temperature is high. Is performed to lower the adjustment.
[0030]
Then, as shown by a virtual line in the graph of FIG. 3, when the dust supply efficiency (ton / cycle) increases, the control means C performs a primary control by the primary combustion air supply means A in the air amount adjustment control. The target value of the supply amount of the combustion air is corrected to the increasing side. That is, as shown in FIG. 5, the target value of the total amount of air supplied to all the treatment zones 5a, 5b, 5c of the combustion treatment zone 5 is corrected to the increasing side. Specifically, when the dust supply efficiency increases and exceeds the set value Kt, the target value of the total air supply amount is increased by, for example, about 10% (that is, the correction rate (%) is set to 10%).
[0031]
Further, as shown by a virtual line in the graph of FIG. 4, when the dust supply efficiency (ton / cycle) increases, the control means C performs the primary combustion by the primary combustion air heating means B in the temperature adjustment control. The target value of the air heating temperature is corrected to the higher temperature side. Specifically, as shown in FIG. 6, when the dust supply efficiency increases and exceeds a set value Kt, the heating temperature (target value) of the primary combustion air is increased.
FIGS. 5 and 6 show an example in which the correction amount for the target value of the air supply amount and the heating temperature is rapidly changed with respect to a change in the dust supply efficiency (a) and an example in which the correction amount is smoothly changed (b). Is shown, but other characteristics may be set.
[0032]
[Another embodiment]
In the above embodiment, when the dust supply efficiency (ton / cycle) increases, the control means C increases the supply amount of the primary combustion air by the primary combustion air supply means A in the air amount adjustment control. For the correction, the total amount of air supplied to all the processing zones 5a, 5b, 5c of the combustion processing zone 5 is configured to be corrected to the increasing side. However, the present invention is not limited to this. The configuration may be such that at least one of the supply amount, the air supply amount to the combustion processing zone 5b, and the total air supply amount to all the processing zones 5a, 5b, 5c is corrected to the increasing side.
[0033]
Further, in the above embodiment, in the temperature adjustment control, the detection information of the furnace outlet temperature detecting means 25 for detecting the furnace outlet temperature (the temperature of the exhaust gas from the furnace) is used as a combustion index indicating the combustion state of the refuse in the furnace. However, besides this, for example, detection information of the amount of steam generated from the waste heat boiler 7, image information of a television camera for detecting a burn-off point on the combustion treatment zone 5b, and information in the furnace Detection information of the calorific value of the dust may be used as the combustion index.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing the entire configuration of a refuse incinerator. FIG. 2 is a block circuit diagram of a control system. FIG. 3 is a graph showing adjustment control characteristics of a combustion air supply amount. FIG. 4 is adjustment control of a combustion air heating temperature. FIG. 5 is a graph showing a correction control characteristic of a combustion air supply amount. FIG. 6 is a graph showing a correction control characteristic of a combustion air heating temperature.
3 incinerator 4 dust supply means 5 incineration treatment zone 5a drying treatment zone 5b combustion treatment zone 5c post-combustion treatment zone 25 furnace outlet temperature detection means A primary combustion air supply means B primary combustion air heating means C control means

Claims (4)

Primary combustion air supply means for supplying primary combustion air below an incineration zone for incinerating refuse supplied into the furnace by dust supply means; and a primary combustion air supply means based on a combustion index indicating a combustion state of the refuse in the furnace. Control means for adjusting the supply amount of the primary combustion air by the combustion air supply means is provided,
A combustion control device for an incinerator, wherein the control means corrects the supply amount of primary combustion air by the primary combustion air supply means to an increasing side when dust supply efficiency indicating a dust supply amount of the dust supply means increases. In the incineration treatment zone, a drying treatment zone, a combustion treatment zone, and a post-combustion treatment zone are sequentially arranged from the upstream side along the garbage transport direction,
2. The control unit according to claim 1, wherein at least one of the air supply amount to the drying treatment zone, the air supply amount to the combustion treatment zone, and the total air supply amount to all treatment zones is increased. Combustion control device for incinerator. Primary combustion air heating means for heating the primary combustion air supplied below the incineration zone for incinerating the refuse supplied into the furnace by the dust supply means, and a combustion index indicating the combustion state of the refuse in the furnace. Control means for adjusting the heating temperature of the primary combustion air by the primary combustion air heating means.
A combustion control device for an incinerator, wherein the control means corrects the heating temperature of the primary combustion air by the primary combustion air heating means to a higher temperature side when the dust supply efficiency indicating the dust supply amount of the dust supply means increases. The control means, as the control for adjusting the primary combustion air heating temperature based on the combustion index, based on the detection information of the furnace exit temperature detection means for detecting the furnace exit temperature as the combustion index, when the furnace exit temperature is low 4. The combustion control device for an incinerator according to claim 3, wherein the controller performs an adjustment control for increasing a heating temperature of the primary combustion air and decreasing a heating temperature of the primary combustion air when the furnace outlet temperature is high.

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